For some time, known flush water tank device operating devices for starting the supply of flush water to a toilet by operating to start the opening of a discharge valve on a flush water tank device for supplying flush water to a toilet have included those in which, as noted for example in Patent Document 1 (Japanese Patent Unexamined Publication No. 2014-190131), in a discharge valve device for opening and closing a discharge port on a flush water tank by up and down movement (“direct-drive discharge valve device”), the amount of up and down movement of the discharge valve body is controlled by controlling the amount of movement of an operating wire, for example the amount by which an operating wire connected to a discharge valve body is pulled up (or the amount by which the operating wire is wound).
Such a conventional operating device for a flush water tank device noted in Patent Document 1 comprises an operating portion such as an operating handle or the like which can be rotationally operated by a user, and a pulley for winding up an operating wire in tandem with the rotational movement of this operating portion. Also, the operating portion and pulley are mutually constantly linked, irrespective of operating state, and the amount of flush water supplied from the flush water tank device to the toilet is determined by the time from the start of the discharge valve opening operation by rotating the operating portion and pulley at an initial position so that the operating wire is wound in, until the discharge valve body drops with the descent of the water level inside the flush water tank to close the valve, i.e., the operating time from the start to end of the operation by the operating portion (operating portion operating time), or by the amount of time the discharge valve body is open (the discharge valve body valve opening time).
Hence, for example, the longer the time during which the operating handle and pulley are maintained in a rotated state, the operating wire is maintained in a wound state, and the discharge valve body is maintained in a pulled up state, the longer the operating portion operating time or discharge valve body opening time will extend, and the greater the amount of flush water supplied from the flush water tank device to the toilet.
In recent years, on the other hand, due to water conservation in toilet flushing, the amount of flush water usable for a toilet flush has been reduced, for example, to a regulation amount of 3.8 L, but depending on the length of the operating portion operating time, the discharge valve opening time may be longer than the valve opening time over which toilet flushing can be sustained within the regulated flush water amount, making it difficult to flush the toilet while controlling the flush water amount to within the regulated amount. Also, in the above-described conventional flush water tank device operating device, wherein the operating portion and the pulley are mutually constantly linked regardless of operating state, or the operating portion is operated manually, there are limits in the degree to which the operating portion operating time can be shortened, leading to a problem of poor operability and usability.
In addition, in an operating device for a flush water tank device, a rotary operation to raise an operating portion or a rotary operation to push down an operating portion are conventionally performed at the start of each toilet flush to wind the operating wire onto a pulley rotating in a predetermined valve opening direction and open a discharge valve body, and thereafter the operating wire is unwound by rotating in a predetermined valve closing direction, thereby closing the discharge valve body.
In particular, the operating portion after the discharge valve body has been fully opened is arranged to return by gravity alone to an initial position at which the next discharge valve opening operation can be started, but if the operating portion returns slowly at a relatively low speed, the rubbing resistance of the rotary shaft linked to the operating portion or the pulley and resistance of other related functional parts may be very influential, such that the operating portion will not necessarily be restored correctly to its initial position. This then becomes an obstacle to maintaining the operating performance of an operating device capable of accurately operating in each repeated toilet flushing.